xx the First Two Centuries 297 to give up the plantation system and let their land to small- holders. The emperors were the first to begin this system on their estates. The East followed suit: the owners of large and middling estates lived in towns and had their land culti- vated by smallholders who were in many cases bound to the soil they tilled. These conditions were unfavourable to pro- gressive and scientific cultivation. In spite of more land and more workers on the land, the quality of the work steadily deteriorated. The same fact is observable in a different department— in the exploitation of natural wealth of other kinds. The number of mines and quarries in working increased. The knowledge of their mineral wealth was probably the main reason why some new territories were annexed to the empire. •We may suppose that this motive, among others, induced Claudius to conquer Britain, and Domitian to annex part of south-west Germany ; and at all events the chief attraction of Dacia was its auriferous sand and wealth in other minerals. Here again, beyond question, the sources of the empire's wealth were added to. But the skill of the workers did not keep up with the development of mines. In mining and metallurgy the Romans did not improve upon the methods of the Hellenistic Age, but even lost ground. The treasury, in other words, the emperor, had worked the mines through substantial contractors employing slaves in great numbers; but now a different method was tried : the work was parcelled out among petty adventurers who had to rely on their own efforts and the help of a few slaves. Under such conditions technical improvements wrere of course impossible. Symptoms of this kind are visible in manufacture as well as in agriculture and mining. Districts which had formerly depended upon imports from the large manufacturing centres now began to take a share in production. Hence, the large centres lost their economic position and grew impoverished. The worst plight of all was that of Greece, whose manufactures disappeared almost entirely from the world's market. A few kinds, indeed, of manufactured articles, some of which cannot be called luxuries, were still produced by special districts and exported thence to the ends of the earth, the vast extent of the Roman Empire 'being a great furtherance to exporta- tion. Some fabrics were still a speciality exported all over the world by Asia Minor, Italy, and Gaul; the copper vessels